We have now a fix to test in the 1.6.6a support build (master).

I have tested the fix and as i thung after the post of "Fretzl", the results are inverted with the results obtained in "Exifer library". In the old Exifer library, an information as 'EF70-300mm f/4-5.6L IS USM' was put in "EXIFLensInfo" collumn and the "ExifLensType" was null.
Now with the fix this information is put in "ExifLensType" column, it's correct on the principle because it's corresponding with the lens model but how read now the olds data who are all writed in the "EXIFLensInfo" column.
The Exif data "UndefinedTag:0xA434" corresponding with 'EF70-300mm f/4-5.6L IS USM' not put at the good place in the actual database.

I am not sure I understand the problem. The old lib was very old and there is naturally a chance it didn't do things properly.

We mapped the "undefinedTag" ones to the corresponding named LensInfo and LensType Exif fields as discussed above and therefore to their matching database columns.

I really like to hear more oppinions before we work more on this.

Maybe it was reversed (and wrong) in the old Exifier library.
Please refresh metadata of your images and also refresh the database.
I found that the metadata information in the database is very persistent.

I understand, many thanks. I renamed the column "EXIFLensInfo" as "EXIFLensType" in database and vice versa. All is operating on my site with 1.6.6a version.
https://rvm-photo.fr in french and an example of exifs on
https://rvm-photo.fr/urbain/architecture/Convergence-20240903-IMG_0570.jpg

I renamed the column "EXIFLensInfo" as "EXIFLensType" in database and vice versa.

Not sure what you mean, we have both columns already by default. I assume you mean the field config instead. Remember any "Hacking" is on your own risk and you have to redo it on every update.

Anyway, we are following the exif specs according to https://exiftool.org/TagNames/EXIF.html.

Another small change: We figured we internally used "LensType" which should actually be named "LensModel" according to the specs. So we updated the internal catalogue while the db column remains unchanged.